Sea Tel ST88-21 C/Ku-Band TVRO, Installation And Operation Manual

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ST88-21 C/Ku-Band TVRO Setup – Targeting
8-1
8. Setup – Targeting
The procedure for optimizing the targeting of the antenna to land on or near a desired satellite (/-1 degree) is outlined
below.
8.1. AUTO TRIM
The Auto Trim function will automatically calculate and set the required Azimuth and Elevation trim offset parameters
required to properly calibrate the antennas display to the mechanical angle of the antenna itself, while peaked ON
satellite. It will also calculate, and set, the proper Auto-Threshold value for this system to use on the desired/targeted
satellite.
To enable this function, the Antenna MUST be actively tracking the satellite with positive SAT ID and elevation of the
antenna must be less than 83 degrees and the ACU must NOT be set for Inclined Orbit Search. After locating the
satellite, with Tracking ON, wait at least 30 seconds before performing the AUTO TRIM feature, this will allow sufficient
time for the antenna to peak up on signal. It is equally important that you verify that the system is tracking the
CORRECT satellite (verify video is produced on the Televisions in a TVRO system or verify a RX lock indication on the
satellite modem in a VSAT system).
While in the AUTO TRIM sub-menu, press the
LEFT
arrow key to bring start the calibration procedure, the display
should read AUTO TRIM SETUP, press the ENTER key to submit. AUTO TRIM SAVED will be displayed, indicating the
proper AZ and EL trims were submitted to RAM. This does not save these parameters to NVRAM, in order to save to
memory, continue down through the setup mode parameters until the SETUP
SAVE NEW PARAMETERS
sub menu
is displayed. Press the
RIGHT
arrow and then press the
ENTER
key. The display should now report that the
parameters were saved. From the AUTO TRIM SETUP screen, press the NEXT key (DAC2202) without hitting ENTER
to escape this screen without submitting the new AZ and EL Trim values.
NOTE:
AUTO TRIM LOCKED will be displayed on the front panel, indicating that the AUTO TRIM Feature is
NOT
allowed if all of these conditions are not met:
The ACU
must
be actively tracking a satellite (AGC above threshold)
and
The ACU
must
have positive SAT ID (internal NID match or external RX lock received from the Satellite
Modem)
and
The elevation angle of the antenna must be LESS than 75 degrees and
The ACU
must
NOT be set for Inclined Orbit Search.
8.2. Manually Optimizing Targeting
First, assure that all of your ship and satellite settings in the ACU are correct.
1. Target the desired satellite, immediately turn Tracking OFF, and record the Azimuth and Elevation positions in
the “
ANTENNA”
display of the ACU (these are the
Calculated
positions).
2. Turn Tracking ON, allow the antenna to “Search” for the targeted satellite and assure that it has acquired (and
peaks up on) the satellite that you targeted.
3. Allow several minutes for the antenna to “peak” on the signal, and then record the Azimuth and Elevation
positions while peaked on satellite (these are the Peak positions). Again, assure that it has acquired the
satellite that you targeted!
4. Subtract the Peak Positions from the Calculated Positions to determine the amount of Trim which is required.
Refer to the ACU Setup information to key in the required value of Elevation Trim.
5. Continue with Azimuth trim, then re-target the satellite several times to verify that targeting is now driving
the antenna to a position that is /- 1.0 degrees of where the satellite signal is located.
EXAMPLE: The ACU targets to an Elevation position of 30.0 degrees and an Azimuth position of 180.2 (Calculated),
you find that Peak Elevation while ON your desired satellite is 31.5 degrees and Peak Azimuth is 178.0. You would
enter an EL TRIM value of –1.5 degrees (displayed as -0015) and an AZ TRIM of +2.2 degrees (displayed as 0022).
After these trims values had been set, your peak
on satellite
Azimuth and Elevation displays would be very near 180.2
and 30.0 respectively.